Blenheim Police are investigating a complaint from a woman that she was sexually assaulted in Eltham Road between Rogers and Stratford Streets about midnight last night.
Detective Sergeant Dave Woodley of Blenheim CIB said Police had conducted a scene examination this morning and were interviewing the victim and her associates.
He said Police would like to hear from anyone who was in Eltham Road in the area between Rogers and Stratford Streets around midnight last night.
They would also like to hear from anyone who heard any sort of commotion in the area last night.
Anyone with information can contact Marlborough CIB, Ph 578 5279.
Information can be given anonymously by calling Crimestoppers, Ph 0800 555 111.